The present invention relates to a counterbalance for use on a press and an improved cushion construction. In certain press operations, it is desirable to provide a counterbalance on a press. A typical construction for such a counterbalance is disclosed in U.S. Pat. No. 2,084,066, issued June 15, 1937, to F. J. Rode et al., entitled, "Metalworking Press". The Rode metalworking press utilizes a pneumatic cylinder embodying piston rods connected to pistons within cylinders to act as counterbalancing devices. The use of various additional systems for counterbalancing various presses is shown in the following patents: U.S. Pat. Nos. 1,970,134, issued Aug. 14, 1934, to W. Ferris, entitled, "Hydraulic Press"; 2,483,597, issued Oct. 4, 1949, to C. E. Schogren, entitled, "Supplemental Forging Press Die"; 3,115,676, issued Dec. 31, 1963, to O. F. Quartullo entitled, "High Speed Forging Apparatus"; 3,776,020, issued Dec. 4, 1973, to Fedosenko et al., entitled, "High-Speed Pressing Maching"; 3,834,216, issued Sept. 10, 1974, to Shiller et al., entitled, "Forging Press"; 3,914,975, issued Oct. 28, 1975, to Kawano, entitled, "Hydraulic Press Brake"; 4,148,209, issued Apr. 10, 1979, to Bessho, entitled, "Forging Press"; and 4,291,571, issued Sept. 29, 1981, to Claussen, entitled, "Forging Press". In addition, West German Auslegeschrift No. 1 294 334, published May 8, 1969, discloses a cylinder construction for use with a press, as does USSR Publication Nos. 338 034 and 1 031 617, of Sept. 15, 1981 and July 30, 1983, respectively.
In those prior art devices wherein pneumatic cylinders are used, there is generally air leakage in the cylinder which requires air to be replenished to the cylinder, thereby increasing the operating costs of the press.
Stacking of the resilient bellows is well known and accepted in the transportion industry. U.S. Pat. No. 2,773,686, issued Dec. 11, 1956, to C. B. Nash, entitled "Air Spring" discloses a construction wherein two bellows are interconnected. The Nash connector utilizes a conventional construction. The conventional construction for bellows of this type is also shown in the following patents: U.S. Pat. Nos. 2,827,283, issued Mar. 18, 1958, to K. A. Browne et al., entitled, "Air Spring With Damping Valve"; 2,887,069, issued May 19, 1959, to R. L. Lich, entitled, "Air Spring Railway Truck"; 2,902,291, issued Sept. 1, 1959, to L. B. Walker, entitled, "Vehicle Pneumatic Suspension System"; and 2,999,682, issued Sept. 12, 1961, to E. Stump, entitled, "Pneumatic Spring System For Motor Vehicles". This means for connecting the bellows to another portion requires the utilization of a plurality of bolts, which in many instances, are difficult to install and provide an opportunity to allow air to leak.
It is an objection of the instant invention to provide an improved counterbalance counstruction and a cushion which reduces air loss to a minimum.
It is a further object of the present invention to provide a pneumatic counterbalance and cushion which may be readily and easily installed.